血培养阳性标本直接细菌鉴定和药敏的探讨

Use of Bact/Alert 3D Positive Blood Cultures for Direct Identification and Susceptibility Testing with VITEK-32 System

目的探讨血培养阳性标本直接细菌鉴定和药敏可行性。方法采用全自动血液培养系统Bact/Alert3D和自动细菌鉴定系统VITEK32前瞻性研究的方法,对359例血培养阳性标本经染色,根据形态、数量多少,选择出290例Bact/Alert3D血培养阳性标本,经多次离心处理后,菌悬液直接用VITEK32细菌鉴定和药敏,同时用VITEK32细菌鉴定和药敏的标准法进行,二者阳性球菌均用GPI、GPS106,阴性杆菌用GNI+、GNS506。结果290例细菌包括223株甲型副伤寒沙门菌、8株大肠埃希菌、30株金黄色葡萄球菌、12株表皮葡萄球菌、9株溶血葡萄球菌、8株腐生葡萄球菌;直接法和标准法符合率:细菌鉴定总符合率93.1%,其中杆菌95.7%,球菌83.1%;药敏:重要误差:杆菌1.3%,球菌5.1%;主要误差:杆菌2.2%,球菌3.4%;次要误差:杆菌3.1%,球菌3.4%;总误差率7.6%。结论Bact/Alert血培养阳性标本直接VITEK32细菌鉴定和药敏对肠杆菌和葡萄球菌是可行的,可大幅度缩短时间,为临床及时修正用药提供依据,结合革兰染色和临床表现,Bact/Alert血培养阳性标本直接VITEK32细菌鉴定和药敏具有较高应用价值。

OBJECTIVE To discuss the possibility of positive blood culture sample for direct identification and antimicrobial susceptibility tests. METHODS We performed a prospective study in which specially processed fluid from positive blood culture bottles by Bact/Alert 3D. Organism identification and susceptibility results were compared with those obtained from cards （GPI, GPS-106, GNI^＋ , GNS-506） inculated with standardized bacterial suspension obtained following subculture to chocolate agar plates, 290 of 359 consecutive positive monomicrobic blood cutures,consisting 231 strains of Gram-negative rods and 59 of Gram-positive cocci, were included in the study. RESULTS For gram-negative organisms, 95.7% showed complete agreement with the standard for species identifi- cation, while for Gram-positives it was 83.1%, the overall agreement was 93.1%. For Gram-negative rods in the drugs tested agreements between the direct and standard methods by GNS-506 cards, the very major error rate was 1.3%, the major error rate was 2.2%, and mild error was 3.0%. For Gram-positive, by GPS-106 there were 5.1%, 3.4%, and 11.9%, respectively. CONCLUSIONS These findings suggest that VITEK-32 cards inoculated directly from Bact/Alert culture positive bottles provide acceptable bacterial identification or susceptibility testing for Enterobacteriaceae and Staphylococcus. The time lapse between initial inoculation of blood culture and the reporting of results shortens.